if(bSpeed_Count >= SPEED_LOOP_RATE)  // Is it Duty update?，
            {
                bSpeed_Count = 0;  //clear count
                if(bCurrent_Duty < _bTarget_Duty)  //
                {
                    // If current duty less than target, current duty + 1
                    if(bCurrent_Duty < MAX_SPEED)//
                        bCurrent_Duty++;
                }                                 
                else  // If current duty more than target, current duty - 1     
                    if(bCurrent_Duty > _bTarget_Duty)       //
                    {
                        if(bCurrent_Duty > MIN_SPEED)
                            bCurrent_Duty--;
                    }
这个 bCurrent_Duty++后还要判断上一个if吗